Spinal Cord/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A boy, Tim, is sitting on an examination table in a doctor's office. A robot, Moby, stands behind him. Moby is using the hand of a model skeleton to scratch Tim's back. TIM: Ah, a little to the left, and a little to the right. Down a bit. Hey, your hand feels bony! Tim realizes what Moby is doing. He pulls away. TIM: Guh-yugh. Tim reads from a typed letter. TIM: Dear Tim and Moby, What does the spinal cord do? From, Olivia. TIM: Your spine supports your whole back, and it’s the reason you can stand up straight, bend over, and turn side to side. Moby points out the spine on the skeleton. TIM: Along with the brain, the spinal cord is part of your central nervous system. In fact, the spinal cord is an extension of the brain stem. An animation shows a human brain, along with a spinal cord running down the center of a spine. TIM: Your spinal cord is only about as wide as your finger, and it's made of neuron bundles that carry impulses from your body to your brain and from your brain to your body. A canal in its center contains a special fluid that provides nourishment to the cord's cells and also acts as a shock absorber. A large cross-section of the spine expands from the illustration to show the canal running through the center of the spine. TIM: The gray matter that surrounds the central canal contains the cell bodies of motor neurons that are responsible for voluntary movements, reflexes, and internal functions. The gray matter is labeled on the cross-section. It is the middle layer. TIM: The white matter contains the parts of these nerve cells called axons, which relay information to and from the brain. The white matter is labeled in the cross-section. It is the outermost layer. TIM: Three layers of connective tissue called meninges protect the spinal cord. The meninges are labeled on the cross-section. They connect the spinal cord vertically. TIM: The amount of gray and white matter in the spinal cord shifts depending on the part of the cord we're looking at. In the cervical part of the spine, there is more white matter because lots of information is traveling back and forth between the brain and that area of the spine. In the lower part of the spine, there is less information exchange and less white matter. An animation points out the parts of the spinal cord that Tim describes. TIM: Surrounding and protecting the spinal cord are bones called vertebrae. Moby holds up a model of a single vertebra. TIM: Not all vertebrae are created equal. They are different shapes and sizes based on their position and function in the spinal column. An animation shows a spinal column, with vertebrae of different shapes and sizes. TIM: There are eight cervical vertebrae in your neck, then 12 thoracic vertebrae in your upper back, five lumbar vertebrae and five sacral vertebrae in your lower back, and one coccygeal vertebra in your tailbone. Labeled move down the spine, pointing out the different types of vertebrae as Tim names them. TIM: This may seem like a lot of protection, but the spinal cord is really important, relaying commands from your brain to the rest of your body. And your spinal cord is responsible for automatic reflexes, like when you instinctively pull your hand away from something hot. An animation shows a hand touching a hot pan on a stove, then pulling back. TIM: And that's your spinal cord. MOBY: Beep. Moby smiles. He is standing next to the skeleton. He has put a wig and a dress on the skeleton. TIM: Um, yes. She's very pretty. MOBY: Beep. Moby puts his arm around the skeleton's shoulders. TIM: Okay, you're creeping me out.Category:BrainPOP Transcripts